FIG. 8 is a cross-sectional view of prior art wedge clutch 200. Clutch 200 includes hub 202, wedge plate 204, and outer ring 206. Actuation force AF is applied in axial direction AD1 to close clutch 200 (connect mode). Wedge clutch 200 exhibits a tendency to disconnect during the connect mode caused by an axial movement of the hub as follows. Taper angle 208 between wedge plate 204 and hub 202 causes thrust force TF in direction AD2, opposite direction AD1. For increasing torque hub 202 is held approximately in a same axial position due to frictional contact at the connection, for example a spline, between hub 202 and a shaft (not shown). When the relative rotation direction between hub 202 and outer ring 206 changes, torque immediately disappears, while contact forces are still present in the system. As a result, thrust force TF created at the taper between hub 202 and wedge plate 204 pushes hub in axial direction AD2 until thrust force TF is smaller than actuation force AF. At that point, actuation force AF pushes hub 202 back to the original and desired axial location.
The displacement of hub 202 in direction AD2 during the connect mode weakens the connection between wedge plate 204 and hub 202, which can lead to loss of the non-rotatable connection between plate 204 and hub 202 and ring 206 and subsequent opening of clutch 200. Also, if force TF pushes hub 202 far enough in direction AD2, end 210 of hub 202 can extend partly or wholly past wedge plate 204 in direction AD2, either compromising or disabling the functioning of clutch 200. Further, if only partial cycles of torque application are experienced by clutch 200, that is, if clutch 200 is not fully displaced back in direction AD1 by each partial cycle, each successive cycle displaces hub 202 further in direction AD2 for the beginning of the next cycle. As a result, the successive partial cycles can “walk” hub partially or wholly past wedge plate 204 in direction AD2.